Network voicemail systems are capable of offering voicemail services to hundreds or thousands of customers. Voicemail services allow voice messages to be stored for later retrieval by subscribing customers. Each customer is assigned a voicemail box having an associated box number and passcode. Using the passcode, the customer can access the voicemail box to listen to voicemail messages or administer the voice mail box. In a traditional a public switched telephone network (PSTN), the serving telephone company's central office (CO) switch may apply a special dial tone to the customer's line when it is taken off-hook to indicate that a new message is waiting in the customer's voicemail mailbox. The special dial tone is called a Stutter Dial Tone (SDT). SDT is similar to a regular dial tone except that is cadenced initially, typically for about two seconds, followed by a continuous dial tone. The SDT gives an audible indication to the customer that one or more voicemail messages are waiting in the customer's voicemail box.